A big issue here will be how many articulations you want to load at any given time. It seems like you may want to keep everything in midi and bounce at the last minute in case any last minute curves are thrown. That's the way I work too and, after a few curves, thankfully so. the problem quickly becomes having enough articulations available so you don't have to bounce. With a library the size of VSL, I anticipated a mac for the sequencer and kontakt, with the bulk of the VSL samples on two giga machines. That was QUICKLY saturated and I went with another giga machine which got me to a point where I was happy. Many others are happy with less so it really pays to think it through as you appear to be doing.
Can't really help with Logic as i use Digital Performer. I would imagine the overloads are similar in either application which symptomatically suggests more of a cpu rather than ram issue. I run a G5 dual 2.0 and altiverb, kontakt and lots of other au instruments with no problem. Where ram becomes more of and isse is with samples. if you're thinking of Logic/EXS, then you will need a ton of it which has probably been discussed in detail in the exs forum if you need more info.
hang in there!
Can't really help with Logic as i use Digital Performer. I would imagine the overloads are similar in either application which symptomatically suggests more of a cpu rather than ram issue. I run a G5 dual 2.0 and altiverb, kontakt and lots of other au instruments with no problem. Where ram becomes more of and isse is with samples. if you're thinking of Logic/EXS, then you will need a ton of it which has probably been discussed in detail in the exs forum if you need more info.
hang in there!